Naples is a city in Collier County, Florida, United States. As of July 1, 2007, the U.S. Census Bureau estimated the city's population at 21,653. Naples is a principal city of the Naples-Marco Island, Florida Metropolitan Statistical Area, which had an estimated total population of 315,839 on July 1, 2007. Although Naples is officially the county seat of Collier County, the courthouse is located in East Naples. Naples, Florida is one of the wealthiest cities in the United States, with the 6th highest per capita income in America, and the second highest proportion of millionaires per capita in the US.